1. Field of the Invention
This invention relates generally to rolling mills where hot rolled products, typically rods and bars, are formed into rings by a laying head, and the rings are deposited in an overlapping Spencerian pattern on a conveyor where they undergo controlled cooling while being transported to a reforming station. The invention is concerned in particular with an improved method for controlling the rotational speed of the laying head so as to optimize the pattern of rings deposited on the conveyor.
2. Description of the Prior Art
In order to cool the rings being transported on the conveyor in a substantially uniform manner, the ring pattern should optimally be substantially uniform. In order to achieve a substantially uniform ring pattern, the laying head speed should be matched to the velocity of the product. Since the product velocity will vary from time to time due to changing rolling conditions, the laying head speed must be correspondingly adjusted, with failure to do so in a timely fashion resulting in a disruption of the ring pattern on the conveyor.
In the past, laying head speeds have been controlled manually by operating personnel based on their observation of the ring pattern on the conveyor. Thus, differences between product velocities and laying head speeds are not detected and addressed until they begin to distort the ring pattern, which in turn adversely affects uniformity of cooling. This problem is exacerbated where operating personnel are inexperienced and/or inattentive to the mill's changing conditions.
The objective of the present invention is to provide an improved method of maintaining an optimum relationship between product velocity and laying head speed.